Of the lines that Solozhenkin does give, the one I like least is the acceptance of the 5.Qc2 gambit with 5...c5, which is also recommended by Roiz. But you can instead play 5...Bb4+ 6.Bd2 Be7. This was recommended by Greet a few years ago, and can transpose to the anti-Catalan line recommended by ... Roiz! For a practical OTB player I think it makes more sense to use this line against both the Catalan and the 5.Qc2 gambit. That's no criticism of Roiz: if he says accepting the gambit is best, who am I to argue?

Greet recommended that in his book, but White does not fianchetto immediately. 5...Ab4+ 6. Ad2 Ae7 7. e4 is the critical continuation. Black has to play ...d5 like in light square Bogo Indian strategy. The game becomes complicated sinne White pushes e5 and becomes similar to a French structure.

All elites seem to prefer 5...c5, but you know how it goes, they like to defend with 30+ move preparation

Of the lines that Solozhenkin does give, the one I like least is the acceptance of the 5.Qc2 gambit with 5...c5, which is also recommended by Roiz. But you can instead play 5...Bb4+ 6.Bd2 Be7. This was recommended by Greet a few years ago, and can transpose to the anti-Catalan line recommended by ... Roiz! For a practical OTB player I think it makes more sense to use this line against both the Catalan and the 5.Qc2 gambit. That's no criticism of Roiz: if he says accepting the gambit is best, who am I to argue?

You may wish to know that he doesn't provide anything against the move order 1.d4 Nf6 2.c4 e6 3.g3, which rules out a Queen's Indian. I found this surprising, given his coverage of move orders starting 1.Nf3 and 1.d4 Nf6 2.Nf3.

Roiz (Quality Chess) starts from the position after 1.d4 Nf6 2.c4 e6 and proposes 3.g3 Bb4+. His lines mostly transpose to the Catalan (which he covers) or the Nimzo (for which he refers to his book on the subject).

He goes into an English (1.Nf3 Nf6 2.c4 b6 3.g3 c5), but the double fianchetto rather than the Hedgehog. This is similar to Khalifman's recommendation in the old Karpov book, though Karpov himself was happy to play the QID with ...Bb7.

[Does anyone know why, if you quote a post with "QID" in it, the forum software replaces "QID" with "2A100C0F020D0A6300"?]

The first chapter makes me curious. How does he avoid being move ordered into a Bb7 QID or a hedghog? I always thought that if you play the Ba6 lines you should forgot about playing the QID set up against 1.Nf3 and study an independant system.